The purpose of this research project is to investigate the relationship of nutrition to susceptibility to cholera infection. Nonhuman primates are used as a model. It was established that intake of 50 percent less protein than in the normal monkey diet increased the number of animals becoming ill with cholera after the administration of 2-5, and 10-15 MID50 V. cholerae. The excretion of vibrios also lasted longer. The results were even more significant when the animals were kept on a practically protein-free diet for a relatively short time, 8 to 12 weeks. Calorie deficient diet with full protein intake did not produce such results. It was observed that the absorption of folic acid and the production of proteolytic and lipolytic enzymes were reduced whereas amylase showed little changes and the D-xylose absorption was not altered greatly. Future experiments are planned using the same challenging doses of V. cholerae in animals on normal diet, as well as on feed with low protein and calories; low protein and low B-vitamin complex; low calories and B-vitamin complex. Preliminary tests showed that even before clinically manifest malabsorption sets in and liver and intestinal biopsies do not reveal histologic changes, malabsorption and lower bactericidal or bacteriostatic levels of enzymes influencing the multiplication of cholera vibrios may develop. The work in progress is aimed at the investigation of the occurrence of these phenomena.